1. Technical Field
The present invention relates to an umbrella structure. More particularly, the present invention relates to an improved umbrella structure in which a torsion spring is provided where each rib is pivotally connected to the corresponding stretcher, and in which each torsion spring can provide an elastic restoring force for opening the canopy, thereby allowing the umbrella structure to be opened with more ease and less effort.
2. Description of Related Art
Umbrellas and parasols (hereinafter collectively referred to as umbrellas) are available in a great variety, including portable compact umbrellas, large beach umbrellas, and garden umbrellas, to name only a few. While umbrellas differ in size and configuration, their functions are more or less the same, i.e., to protect against rain and/or sunlight.
In terms of manufacture, different types of umbrellas are often equipped with different parts or devices to facilitate opening. For instance, a large beach umbrella or garden umbrella is typically provided with a pulling cord and a rotating handle so that the runner can be pulled via the rotating handle and the puling cord to open the umbrella. Some portable, automatic compact umbrellas have a spring and related parts installed in their shafts and are opened by means of the elastic restoring force of the spring, which drive the runner to slide.
However, the shaft of such a conventional automatic umbrella tends to be relatively thick and heavy due to the spring and the related parts installed therein. The plurality of parts also contribute to structural complexity and consequently higher risks of function failure.